Sharpening device



Feb. 14, 1939. L 5 SHAW 2,147,464

SHARPENING DEVICE Filed Dec. 29, 1957 \NVENTOR LOUIS E. SHAW d'z wmw.

ATTORNEYS Patented Feb. 14, 1939 PATENT OFFICE SHARPENING DEVICE Louis E. Shaw, East Orange, N. J.

Application December 29, 1937, Serial No. 182,313

7 Claims.

The invention relates to a household tool sharpening device and particularly relates to a scissors sharpener of the spool-shape type which can sharpen a pair of scissors or shears by drawing the blades across the sharpener which is held between a thumb and finger of one hand.

The primary object of the invention is to provide a simple form of sharpening device for sharpening any of the usual makes of scissors,

and is particularly designed to permit the unshearing edge of the blades of such scissors.

It has been known heretofore, as exemplified in the patent to Collum, No. 479,737, issued July 26, 1892, to provide a similar form of scissors sharpener. With such forms of devices, however, the sharpening is effective solely in those cases where the edges of the blades happen to coincide, when inserted between the guiding flanges of the sharpener, with whatever angle may be formed between the blades when so set and the line of contact with the cylindrical sharpening hub. It is a fact, however, that different scissors and shears manufacturers bevel the cutting edges of the blades at various angles, sometimes depending upon the character of material intended to be operated on by the shears or scissors. It is obvious then that with such known forms of such sharpening tools, only one form of shears or scissors can be efficiently ground or sharpened.

Accordingly, an important object of the present invention is to provide a form of scissors sharpen-er which will accommodate itself automatically to whatever angle may be present in the particular shears or scissors for the time being in engagement with the sharpener.

Broadly, this aspect of the invention is attained by rockably mounting the sharpening or burnishing element herein generically referred to as a sharpening element, member or cylinder so that when engaged by any particular angled faces between the blade and the grinding cylinder, he

is very apt, in rocking the blades back and forth across the grinding cylinder and in this rounding 01f opposite edges of the blade, to defeat the very thing which he is endeavoring to attain.

Accordingly, another object of the invention is to provide for the concealing of opposite ends of the grinding cylinder herein featured, so that the operator would not be induced to try to make a fit between the blade and the grinding cylinder, and as a matter of fact the disclosure features a structure which does not obviously disclose its automatically adjustable features.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawing and in part will be more fully set forth in the following particular description of one form of structure embodying the invention, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the accompanying drawing:

Fig. 1 is a view in side elevation of a preferred embodiment of the invention disposed in operative position between the blades of a pair of scissors shown in position to be sharpened;

Fig. 2 is an enlarged axial sectional view through the sharpening device of Fig. 1 when in its normal position free of the scissors; and

Fig. 3 is a similar view showing the scissors blades in position to be sharpened taken on the line 3-3 of Fig. 1.

In the drawing, the sharpener it is of spoolshape configuration and comprises a tubular spacing and mounting hub H having a bore l2 extending axially therethrough. The hub is of maximum diameter at its mid-portion and gradually reduces in diameter therefrom towards its opposite ,ends to form a double, frusto-conical tube, the outer surface of which has a double laper. A pair of holding discs I3 and Hi at opposite ends of the hub constitute means for holding the device as a whole between a thumb and finger of one hand while holding the scissors with the other. The discs also constitute means for approximately locating in position the blades (1, b, of the scissors C to be sharpened and to this extent may be regarded as a blade guiding means functioning to limit the permissible lateral move ment of the blades while in operative position. Each disc is shown to be a stamping of thin metal with a concaved outer side l5 contoured for receiving the thumb or finger of the operator. The central portion of each disc is pressed outwardly to form a circular, shallow, disc portion It, the center of which is provided with a rivet hole H aligned with the bore l2. The marginal portion iii of each disc considered outwardly of the disc portion l6 forms roughly a segment of a sphere and provides on its inner face W a convex guiding surface which coacts with its companion to locate between the portions 18 of the two discs, the blades (1 and b of the scissors.

A rivet 20 extends through the holes I! and bore l2 and the heads at opposite ends acts to secure the discs fixedly to the hub. A sleeve-like sharpening cylinder 2| loosely encircles the hub so as to have freedom of rotary movement about its axis and due to the elevated center and relatively lowered ends of the hub, the cylinder 2| also has a limited degree of rocking movement about axes transverse of the cylinder axis. Opposite ends of the cylinder 2| are intruded within the disc portions I6 and thus concealed from view in all rockable portions of the cylinder.

It is noted that the shearing edges (2 and e respectively of the blades a and b form a certain angle with respect to the blades and specifically with respect to the shearing plane fg common to the inner faces of the two blades. This angle varies with the different sizes, makes and character of scissors and shears commonly found in most households. The feature of this disclosure is that the cylinder 2| is. not only free to rotate about its own axis, thereby to present fresh surfaces in succeeding sharpening or burnishing operations, but also accommodates itself automatically to whatever angle may be presented by the surfaces e-d of the scissors which for the time being is in engagement therewith.

In operation, the operator grasps the spoollike device by engaging the end discs between a thumb and finger, then with the scissors in the position shown in Fig. 1, they are simply drawn across the cylinder 2| while the blades are engaging the same firmly and simulating the act of cutting the cylinder 2|. As the blades initially engage the cylinder, the edges de simultaneously tilt the cylinder 2| from whatever position it may have into an angled position and eventually the blades assume the position shown in Fig. 3 in engagement with opposite sides of the cylinder 2|. At any instant of time then the cylinder 2| presents two parallel lines of sharpening or rather burnishing surfaces such as shown by the lines d and e in Fig. 3, one for each blade and each line is located exactly parallel to and in engagement with the line of contact with its associated blade edge irrespective as to what might be the angle of the blade edge. In burnishing the edges as herein suggested there is very apt to be formed a slight burr which projects beyond the plane indicated by the line f-g but which burr is sheared off simply by causing the blades to be closed on each other past their cutting edge as in their shearing action.

As the sharpening cylinder 2| is not required to have the structural strength necessary to provide its own hub, it may be made of relatively small cross sections of material and thus may be made of a case hardened steel or other expensive sharpening material without unduly adding to manufacturing cost. It is suggested that the cylinder 2| need not be of metal but may be of any other material such as glass, and, in fact, any material harder than the material of the blades a -b. Preferably, the outer surface is smooth to provide a burnishing effect, usually all that is necessary to sharpen scissors, but it may be given a roughened surface as by milling or it may be coated with some form of abrasive such as emery or pumice stone where a grinding effect is desired.

The design particularly lends itself to cheap production as the component parts, except possibly the sharpening cylinder, may be formed as simple machine stampings, and the parts assembled and secured together quickly on a riveting machine by unskilled labor.

I claim:

1. A scissors sharpener of spool-shaped form comprising a tubular spacing and mounting hub having a bore extending therethrough and having its outer surface with a double taper of greatest diameter adjacent its mid-portion and gradually reducing in opposite directions from its mid-portion towards its opposite ends, holding discs at opposite ends of the hub, each disc pro vided at its center with a shallow disc-portion, the marginal portion of each disc, outwardly of the disc portion, forming substantially a segment of a sphere, said disc portions abutting opposite ends of the hub, a rivet passed through the bore and having heads at opposite ends engaging the disc portions to secure the discs to the hub and a sleeve-like cylinder of relatively hard material constituting a sharpening member, encircling and mounted on the hub for free rotary movement about its own axis and for rocking movement about an axis extending transversely of the length of the hub and said cylinder having its opposite ends intruded within the disc portions of the end discs.

2. A scissors blade sharpener of spool-shaped form comprising a hub having holding discs at opposite ends, a sleeve-like blade sharpening cylinder loose on said hub, the outer surface of the hub coacting with the inner surface of the cylinder to provide a clearance therebetween increasing in width towards opposite ends when the cylinder and hub are coaxially disposed there- I by to provide for a limited freedom of rocking movement of the cylinder on the hub, opposite ends of the cylinder intruded into the holding discs and the mid-portion of the cylinder exposed between the holding discs.

3. A scissors sharpener including a hub of double-frusto-conical form with their larger ends integrally connected at the mid-portion of the hub, end discs secured to the smaller ends of the hub and a sleeve-like sharpening cylinder encircling the hub, located between the end discs and having a limited freedom of rocking movement about the enlarged mid-portion of the hub.

4. A scissors sharpener of spool-shape form including a pair of holding discs and a sharpening cylinder mounted between the discs for a limited rocking movement about an axis extendmg transversely to the axis of the cylinder.

5. In a device of the class described, the combination of a hub, a sharpening element mounted on the hub for rotary movement about the axis of the hub and for rocking movement about another axis, said cylinder having a relatively small cross sectional area of material.

6. In a scissors sharpener, the combination of a hub, a freely floating sharpening element mounted on the hub for rotary movement relative thereto about the axis of the hub and for free rocking movement relative thereto for a limited degree about another axis perpendicular to the axis of the hub.

'7. A scissors sharpener including a sharpening tubular cylinder free to move with the part of the scissors in engagement therewith and a supporting hub on which the cylinder is loosely mounted for free rotary and a limited rocking movement.

LOUIS E. SHAW. 

